Electronic musical apparatus for recording and reproducing music content

ABSTRACT

In an electronic musical apparatus, a media ID (MD 1 , MD 2 , MD 3 , MD 4 , MD 5 ) is associated with each recording media of a memory card  8 , hard disk device  10 , flash memory ROM  11 , CD-ROM  12  and internet  15 . Each media ID is encrypted to be recorded on a different position in a ROM  2 . Upon reading a music content, the media ID of the corresponding recording media is decoded to decode the music content based upon the media ID and the secret key, and then, the resultant is temporarily stored in a RAM  3 . Upon writing a music content, it is encrypted based upon the media ID corresponding to a recording media and the secret key, and the content in the RAM  3  is deleted. This makes cryptanalysis hard to thereby enhance a protection level of a music content in an electronic musical apparatus.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an electronic musical apparatus that isaccessible to plural types of recording medias and can read musiccontent, that is encrypted to be recorded, from one optional recordingmedia among the plural types of recording medias and can encrypt themusic content to be recorded to one optional recording media, and to acomputer-readable program applied to this apparatus.

2. Description of the Prior Arts

Conventionally, there has widely been known an electronic musicalapparatus such as an electronic musical instrument or the like that canmake an automatic performance based upon music piece data (performancedata) composed of MIDI data. Further, there has been proposed anelectronic musical instrument that adopts a memory card such as a smartmedia (registered trademark) as an external memory media, wherein theprestored MIDI music piece data is read from this memory card for anautomatic performance or the MIDI music piece data edited or composed bya user is written in the memory card for storage. Moreover, in casewhere MIDI music piece data or the like (hereinafter suitably referredto as “music content”) that needs a copyright protection is read fromthe external recording media or the like, some electronic musicalinstruments give management information including a copyright flag tothe music content for attempting a copyright protection to protectillegal copy.

A CPU adopted in an electronic musical instrument has increased speedyear by year. Further, the electronic musical instrument hasincorporated therein a recording media such as a flash memory ROM,CD-ROM/R/RW drive or the like or it can be connected to these recordingmedias via an interface such as a USB or the like. Therefore, variousrecording medias are being able to be utilized for electronic musicalinstruments. Using plural types of recording medias described aboveleads to the use of various software or various contents, thus enhancinga function of the electronic musical instrument. Moreover, the musiccontent can also be recorded in the various recording medias accordingto the taste of a user. In this case, it becomes necessary to considerthe copyright protection of the music content.

From the viewpoint of the copyright protection, a technique forencrypting music piece data is disclosed in Japanese Unexamined PatentApplication No. 2003-208163. This conventional technique discloses thatmusic piece data is transmitted via a network and this music piece datais taken in an electronic musical instrument to execute an automaticperformance. Further, in this conventional technique, music piece datais encrypted by using a key (secret key) so as not to allow the illegaluse of the auditioning music piece data.

When a secret key is used for an encryption as described above, thesecret key is needed for its decode. Therefore, it is necessary to storethe secret key in, for example, an electronic musical instrument that isalso used as a stand-alone device. Moreover, in case where the musiccontents respectively stored in the plural types of recording medias areencrypted, the use of common secret key simplifies a processing program,but once the secret key is found, the music contents in all therecording medias are easily decoded, thereby entailing a problem that alevel of protection is weak, such as allowing an illegal copy.

SUMMARY OF THE INVENTION

The present invention is accomplished in view of the above-mentionedproblems, and aims to make cryptanalysis hard to thereby enhance aprotection level of a music content in an electronic musical apparatusthat is accessible to plural types of recording medias and can read amusic content, that is encrypted to be recorded, from one optionalrecording media among the plural types of recording medias or canencrypt a music content to be recorded to one optional recording media.

In order to attain the above-mentioned object, an electronic musicalapparatus that can reproduce encrypted music contents each recorded inplural types of recording medias is configured as follows. Theelectronic musical apparatus comprises a storing portion that storesplural media IDs each allocated to each of plural types of recordingmedias, a media ID obtaining portion that obtains, among the pluralmedia IDs stored in the storing portion, a media ID corresponding to therecording media from which a music content is designated to be read, anda reading portion that reads the encrypted music content from therecording media from which the music content is designated to be readand decodes the read and encrypted music content by using the obtainedmedia ID.

This makes it impossible to decode the encrypted music content so longas the media ID corresponding to the recording media on which the musiccontent is recorded cannot be obtained. Accordingly, the music contentsrecorded on the plural recording medias cannot freely be reproduced,thereby enhancing a copyright protection of the music contents.

Further, the encrypted music content may include encrypted common keyinformation independent of the types of the recording media, wherein thestoring portion may further store a common secret key for decoding theencrypted common key information and the reading portion may beconfigured as follows. The reading portion may have a common keyinformation decoding portion that decodes the encrypted common keyinformation by using the common secret key, a decoding key generatingportion that generates a decoding key for decoding the encrypted musiccontent by using the decoded common key information and the obtainedmedia ID, and a music content decoding portion that decodes the read andencrypted music content by using the generated decoding key.

Moreover, the encrypted music content may include encrypted music piecedata representing a music piece, an encrypted music piece data key fordecoding the encrypted music piece data and encrypted common keyinformation independent of the types of the recording media, wherein thestoring portion may further store a common secret key for decoding theencrypted common key information and the reading portion may beconfigured as follows. The reading portion may have a common keyinformation decoding portion for decoding the encrypted common keyinformation by using the common secret key, a decoding key generatingportion for generating a decoding key for decoding the encrypted musicpiece data key by using the decoded common key information and theobtained media ID, a music piece data key decoding portion for decodingthe encrypted music piece data key included in the read and encryptedmusic content by using the generated decoding key, and a music piecedata decoding portion for decoding the encrypted music piece dataincluded in the read and encrypted music content by using the decodedmusic piece data key.

This makes the procedure for decoding complicated, thereby furtherenhancing a copyright protection of a music content.

Further, an electronic musical apparatus that can encrypt music contentsand record the encrypted music contents in plural types of recordingmedias is configured as follows. The electronic musical apparatuscomprises a storing portion that stores plural media IDs each allocatedto each of plural types of recording medias, a media ID obtainingportion that obtains, among the plural media IDs stored in the storingportion, a media ID corresponding to the recording media into which amusic content is designated to be written, and a writing portion thatencrypts the music content by using the obtained media ID and writes theencrypted music content in the designated recording media.

Further, the music content may include common key informationindependent of the types of the recording media, wherein the storingportion may further store a common secret key for encrypting the commonkey information and the writing portion may be configured as follows.The writing portion may have an encryption key generating portion forgenerating an encryption key by using the common key information and theobtained media ID, a music content encrypting portion for encrypting themusic content by using the generated encryption key, a common keyinformation encrypting portion that encrypts the common key informationby using the common secret key, and a music content writing portion thatwrites the encrypted music content including the encrypted common keyinformation in the designated recording media.

Moreover, the music content may include music piece data representing amusic piece, a music piece data key for encrypting the music piece dataand common key information independent of the types of the recordingmedia, wherein the storing portion may further store a common secret keyfor encrypting the common key information and the writing portion may beconfigured as follows. The writing portion may have a music piece dataencrypting portion for encrypting the music piece data by using themusic piece data key, an encryption key generating portion forgenerating an encryption key by using the common key information and theobtained media ID, a music piece data key encrypting portion forencrypting the music piece data key by using the generated encryptionkey, a common key information encrypting portion for encrypting thecommon key information by using the common secret key, and a musiccontent writing portion that writes the encrypted music contentincluding the encrypted music piece data, the encrypted music piece datakey and the encrypted common key information in the designated recordingmedia.

This allows the complicatedly encrypted music content to be recorded inthe recording media, thereby further enhancing a copyright protection ofthe music content.

Further, the music content read from one recording media of pluralrecording medias as described above may be stored in temporal storingportion, and then, the music content stored in the temporal storingportion may be automatically written in the other one recording media bythe manner described above. Specifically, the music content can betransferred among plural types of recording medias with a specificcryptographic process performed every recording media. In this case, themusic content stored in the temporal storing portion may automaticallybe deleted after the music content is written in the other one recordingmedia.

According to this, even if the music content is transferred from onerecording media to the other one recording media among plural recordingmedias, the music content is encrypted and recorded according to therecording media to which the music content is to be transferred, therebyenhancing a copyright protection of the music content.

Further, the invention is not limited to an electronic musical apparatusupon embodying the invention, but it can be embodied as an invention ofa computer-readable program and an invention of a method applied to anelectronic musical apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a hardware configuration of an electronicmusical apparatus and peripherals according to an embodiment of thepresent invention;

FIG. 2 is a view showing an outline of a process to music piece datahandled by the electronic musical apparatus of the embodiment and eachrecording media;

FIG. 3 is a conceptional view showing a data structure of encryptedmusic content and a procedure for decode and encryption;

FIG. 4 is a flowchart showing a main routine in the embodiment;

FIGS. 5A and 5B are flowcharts showing a reading routine in theembodiment;

FIGS. 6A and 6B are flowcharts showing a writing routine in theembodiment; and

FIG. 7 is a flowchart showing a modified example of the main routine.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 is a block diagram showing a hardware configuration of anelectronic musical instrument and peripherals in an embodiment of thepresent invention, wherein a CPU 1 (a control portion) entirely controlsthe electronic musical instrument by using a working area in a RAM 3based upon a control program stored in a ROM 2. As a basic function of ageneral electronic musical instrument, the CPU 1 detects an operationevent of a keyboard or the like at an input operation section 4 tocontrol a manual performance. Further, it detects an operation event ofa panel operation elements or the like at the input operation section 4to perform a process according to the operation of each operationelement. Moreover, it controls a display on a display device 5 such as aliquid crystal panel or the like. A tone generator 6 generates a tonesignal according to various data set from the CPU 1 by a keyboardperformance or automatic performance and outputs the tone signal to asound system 7. The sound system 7 performs D/A conversion oramplification of the tone signal and sounds out the resultant withspeakers.

This electronic musical instrument is, as a recording media or its drivedevice, provided with a memory card reading/writing device 9 thatperforms read/write of data to a memory card 8, a hard disk device (HDD)10 that performs read/write of data to a built-in hard disk, a flashmemory ROM 11 that performs read/write of data to an internal memoryarea and a CD-ROM drive 13 that reads data from a CD-ROM 12. Amongthese, the memory card reading/writing device 9, hard disk device 10 andflash memory ROM 11 are incorporated in the body of the musicalinstrument, while the CD-ROM drive 13 is externally mounted with a USBcable via an interface 14. Further, it is connectable to internet 15 viathe interface 14. Specifically, the memory card 8, hard disk device 10,flash memory ROM 11, CD-ROM 12 and sites of the internet 15 are definedas plural recording medias of different type in this embodiment.

A media ID (hereinafter referred to as “MD1, MD2, MD3, MD4, MD5” in thatorder), each being different from one another, is allocated to thememory card reading/writing device 9, hard disk device 10, flash memoryROM 11, CD-ROM drive 13 and internet connecting section of the interface14 respectively. These media IDs are encrypted and written in apredetermined area of a control program stored in the ROM 2 (a storingportion). By this process, the media ID is set to each recording mediain the electronic musical instrument. Any information is available asthe media ID as long as it can be used as secret key information.Preferably, the pieces of information can be inferred easily and aredifferent from each other.

FIG. 2 is a view showing music piece data handled by the electronicmusical instrument in this embodiment and an outline of a process toeach recording media. A block of “providing music piece data” is aseller of the memory card 8 and CD-ROM 12 having the music piece datarecorded thereon or a site on the internet 15 providing transmissionservice or selling service of the music piece data. The music piece dataprovided by the memory card 8, CD-ROM 12 and internet 15 is encrypted inadvance for the electronic musical instrument by a secret key describedbelow based upon the media ID (the same media ID in the electronicmusical instrument) corresponding to each recording media. The musicpiece data already encrypted is provided by the corresponding recordingmedia.

The encrypted music piece data in the memory card 8 and the CD-ROM 12 isdecoded by the secret key based upon each media ID (MD1, MD4) by reading(LOAD). Further, the encrypted music piece data downloaded from theinternet 15 is decoded by the secret key based upon the media ID (MD5).Each decoded music piece data is stored in a content storing area (atemporal storing portion or temporal storing device) in the RAM 3.Further, the music piece data is encrypted and can be saved in therecording media on which a recording is possible such as the memory card8, hard disk device 10 and the flash memory ROM 11 by a secret key basedupon each media ID. However, the music piece data that needs a copyrightprotection, i.e., the encrypted music piece data cannot be copied butcan only be transferred among the readable and recordable recordingmedias.

FIG. 3 is a conceptional view of a data structure of the encrypted musiccontent and a procedure of decoding and encryption. The data of themusic content is composed of common key information, securityinformation and music piece data. These pieces of information areencrypted respectively. The common key information includes a common keyA set based upon a random value. The security information includes afile name, name of works, copyright information (flag) and content ID.The content ID is a single content ID for whole data of the musiccontent. This content ID functions as a key C (music piece data key)described later for decoding the music piece information. The musicpiece data information includes MIDI music piece data, logical scoredata, style (performance data for accompaniment), registration (data fordesignating a tone or effect of an electronic organ) or the like.

The ROM 2 (a storing portion) stores a control program and media IDs(MD1, MD2, MD3, MD4, MD5) each corresponding to each recording media.These media IDs are stored at the respective places (addresses) apartfrom one another, each ID being subject to different encryption by apredetermined secret key different from every recording media. It shouldbe noted that, since the storing place and encryption process of themedia ID is determined in advance every recording media, the reading anddecoding of the media ID according to each recording media is of coursepossible by the execution of the control program in the electronicmusical instrument. Further, a predetermined secret key AA (commonsecret key) is stored in the control program of the ROM 2. This secretkey AA is for decoding the common key information in the music contentand encrypting the decoded common key information.

In case where the encrypted music content is decoded, the data of thecommon key information is firstly decoded by the secret key AA in thecontrol program to obtain the common key A. Then, the media IDcorresponding to the recording media of the music content is decoded tobe read, wherein a predetermined calculation or the like is performed togenerate a key B (decoding key) for decoding the security information byusing the media ID and the common key A. Further, the securityinformation is decoded by this key B to obtain the content ID therein asa key C (music piece data key). Then, the music piece data informationis decoded by this key C. The keys A, B and C, media ID and music piecedata obtained by this decoding are temporarily stored in the contentstoring area (a temporal storing portion or temporal storing device) ofthe RAM 3 with decoded state. The music piece data or the like is readaccording to the predetermined program to be suitably used for anautomatic performance or the like.

Subsequently explained is a procedure for encryption upon recording thedecoded music content in the memory card 8, hard disk device 10 andflash memory ROM 11. When the security information of the music contentthat is to be encrypted (recorded) is designated, a key B (encryptionkey) is firstly generated by the common key A of the common keyinformation of the music content corresponding to the securityinformation and the media ID of the recording media where the musiccontent is to be recorded. The security information (including thecontent ID (music piece data key)) is encrypted by the key B and thecommon key information including the common key A is encrypted by thepredetermined secret key AA (common secret key) in the control program.Then, the music piece data information is encrypted by the key C (musicpiece data key) that is the content ID before the encryption.

FIG. 4 is a flowchart showing a main routine of the embodiment, FIGS. 5Aand 5B are flowcharts showing a reading routine and FIGS. 6A and 6B areflowcharts showing a writing routine. The process of each routine isperformed based upon the execution of the control program by the CPU 1(a control portion). In the main routine in FIG. 4, a general process ofthe electronic musical instrument is performed at step S1 such as anactivation such as initialization, a process corresponding to theoperation on the operation panel at the input operation section 4, asound-out process based upon the performance on the keyboard at theinput operation section 4, an automatic performance process based uponthe music piece data, a performance guide process such as turning on adepressed key guide lamp, a designating process of the music contenttemporarily stored at the content storing area in the RAM 3, adesignating process of the recording media composed of the memory card8, hard disk device 10, flash memory ROM 11, CD-ROM drive 13 (CD-ROM 12)and internet 15, a designating process of the music content in therecording media or the like.

Subsequently, it is determined at step S2 whether there is aninstruction of loading of the music piece data or not. If there is noinstruction of loading, the program proceeds to step S4. If there is aninstruction of loading, the process of the reading routine in FIGS. 5Aand 5B is performed at step S3, and then, the program proceeds to stepS4. It is determined at step S4 whether there is an instruction ofsaving the music piece data or not. If there is no instruction ofsaving, the program proceeds to step S6. If there is an instruction ofsaving, the process of the writing routine in FIGS. 6A and 6B isperformed at step S5, and then, the program proceeds to step S6. Theother processes are performed at step S6, whereupon the processes atstep S1 and the following steps are repeated unless the process is endedby turning off a power source at step S7.

In the reading routine shown in FIGS. 5A and 5B, it is determined atstep S11 whether the music content is encrypted or not. If notencrypted, the music content is read as it is to be temporarily storedin the content storing area in the RAM 3, and then, the program proceedsto step S26. If encrypted, the processes at the step S13 and thefollowing steps are performed. As to whether the music content isencrypted or not, a general reading operation is carried out, forexample, and the determination may be made that the music content isencrypted if it cannot be read, or the fact that the music content isencrypted in advance may be recorded to the music content.

It is determined at steps S13 to S17 from what type of recording mediathe music content is read, and steps S18 to S22 execute a processaccording to each recording media. Specifically, at steps S18 to S22,the data of the media ID corresponding to the recording media is readfrom the place (address) corresponding to the recording media, fromwhich the music content is read, in the ROM 2, and the read media ID isdecoded, wherein the decoded value (MD1 to MD 5) is stored as thecorresponding media ID. Then, the program proceeds to step S24. If therecording media is not determined to be any one of the recording mediascorresponding to MD1 to MD5, a warning is displayed at step S23 such as,for example, “It is not the recording media handled by this apparatus”or the like, and the program proceeds to step S26.

As explained at FIG. 3, at step S24, the common key information isdecoded by using the secret key AA to thereby obtain the common key A,whereby the key B (decoding key) is generated by the common key A andthe media ID to decode the security information by the key B. The musicpiece data is decoded with the content ID in this decoded securityinformation defined as the key C (music piece data key). Subsequently,at step 25, each key, ID, security information and music piece data aretemporarily stored (virtual storage) in the content storing area in theRAM 3 with the decoded state. Then, the program returns to step S11unless the data to be read is ended at step S26, while the programreturns to the original routine if ended.

The writing routine shown in FIGS. 6A and 6B is activated when the musiccontent is read from the recording media as decoded to be temporarilystored (virtual storage) in the content storing area (a temporal storingportion or a temporal storing device) in the RAM 3 by the process of thereading routine shown in FIGS. 5A and 5B and when the music content isselected at step S1 in FIG. 4 (when the music piece data and thecorresponding security information are designated). Specifically, thewriting routine is a process for encrypting the music content that isdecoded and temporarily stored in the RAM 3 and writing the resultant tothe recording media, in response to the determination of savinginstruction of the music piece data by step S4 in FIG. 4. Firstly, it isdetermined at step S31 whether the music content should be encrypted ornot. If it is not the one that should be encrypted, the music content iswritten in the recording media without being encrypted at step S32, andthe program proceeds to step S44. If it should be encrypted, theprocesses at step S33 and the following steps are performed. Whether themusic content should be encrypted or not is determined by the copyrightinformation (flag) of the security information or the like.

It is determined at steps S33 to S36 on what type of recording media themusic content is written. The process according to each recording mediais performed at steps S37 to S40. It should be noted that steps S51 andS52 shown by a broken line will be described later. At steps S37 to S40,the data of the media ID corresponding to the recording media is readfrom the place (address) corresponding to the recording media, on whichthe music content is to be written, in the ROM 2, and the read media IDis decoded, wherein the decoded value (MD1 to MD3, MD5) is stored as thecorresponding media ID. Then, the program proceeds to step S42. If therecording media is not judged to be any one of the recording mediascorresponding to MD1 to MD5, a warning is displayed at step S41 such as,for example, “There is no recording media on which music content shouldbe written” or the like, and the program proceeds to step S44.

As explained at FIG. 3, at step S42, the key B (encryption key) isgenerated by using the common key A and the media ID to thereby encryptthe security information (music piece data key) by the key B. Further,the common key A is encrypted by the secret key AA. Moreover, the musicpiece data is encrypted with the content ID in this security informationdefined as the key C (music piece data key), and the information of thecommon key A, security information and music piece data are collected asone music content. Then, the music content in which the information ofthe common key A, security information and music piece data arecollected is recorded on the designated recording media and the musiccontent temporarily stored (virtual storage) in the RAM 3 is deleted atstep S43. Then, the program returns to step S31 unless the data to bewritten is ended at step S44, while the program returns to the originalroutine if ended.

The above-mentioned embodiment explains about the case where the CD-ROMdrive 13 performs reading from the CD-ROM 12. However, in case where theCD-ROM drive 13 has a function to write in the CDR/RW, steps S51 and S52shown by a broken line in FIG. 6 may be executed. Specifically, when itis determined at step S51 whether the writing is performed to theCDR/RW, the data of the media ID corresponding to the CDR/RW is readfrom the place (address) corresponding to the CDR/RW in the ROM 2, andthe read data is decoded to be stored as the media ID at step S52. Then,the program proceeds to step S42.

The above-mentioned embodiment does not basically consider remodelingthe device, but in this embodiment, a media ID (media number) common toevery type of the recording media is set to encrypt the music piecedata. Accordingly, when a recording media (other than the flash memory)for a first electronic musical instrument is removed and attached to asecond electronic musical instrument different from the first electronicmusical instrument, the music piece data utilized for the firstelectronic musical instrument can be utilized for the second electronicmusical instrument. The flash memory (ROM) is fixed on a substrate by asoldering, so that it cannot be removed. This can be eliminated asfollows except for the CD-ROM. As for a memory card that is easilyremoved, the one with an ID number is adopted. After a differentencryption is performed for every memory card, data is recorded on thememory card. As for a hard disk device, each one is encrypted based uponeach format/serial number that is a numerical value different from eachhard disk device, and then, recording is performed. This means that a IDstoring portion provided every type of recording media for storing themedia ID is not only provided at the ROM 2 but also provided everyrecording media. According to this, the music piece data can be decodedonly by a single electronic musical instrument.

Further, the aforesaid embodiment independently performs that the musicpiece data recorded on one recording media among plural recording mediasis temporarily stored in the RAM 3 and that the music piece datatemporarily stored in the RAM 3 is recorded on one recording media amongplural recording medias. However, in addition to this, the music contentrecorded on one recording media among plural recording medias can alsobe transferred to the other one recording media among plural recordingmedias. In this case, the CPU 1 executes the main routine shown in FIG.7 wherein processes at steps S8, S3′ and S5′ are added between the stepS5 and step S6 in FIG. 4.

In this main routine, when the music content is instructed to be movedby the process corresponding to the operation on the operation panel atthe input operation section 4 at step S1, the CPU 1 makes “YES”determination at step S8 to automatically successively execute steps S3′and S5′. The processes at steps S3′ and S5′ are the same as those atsteps S3 and S5. It should be noted that, in this case, one recordingmedia having recorded thereon the music content that is to be moved andthe music content in the recording media are designated as well as therecording media to which the music content is moved to be recorded isalso designated. By this, the music content recorded in the designatedone recording media is decoded by the same manner as in theabove-mentioned embodiment and temporarily stored in the RAM 3.Thereafter, the temporarily stored music content is automatically readfrom the RAM 3 to be recorded on the designated one recording media asencrypted by the same manner as in the above-mentioned embodiment.Further, the music content in the RAM 3 is deleted thereafter.

Moreover, the security information is decoded and encrypted by the key Bas well as the music piece data information is decoded and encrypted bythe key C (music piece data key) in the security information in theaforesaid embodiment and modified example. However, instead of this, themusic piece data information and the security information (not includingthe key C that is the content ID) may be decoded and encrypted by thekey B (decoding key and encryption key), omitting the key C (music piecedata key) that is the content ID in the security information.

Further, the invention is not limited to the above-mentioned embodiment,but various modifications are possible without departing from the spiritof the invention upon embodying the present invention.

1. An electronic musical apparatus for reproducing encrypted musiccontents received from any one of plural types of music content sources,the electronic musical apparatus comprising: a storage device forstoring a secret key and a plurality of source IDs each unique to one ofthe plurality types of music content sources; a memory for storingcomputer executable instructions; and a processor coupled to the memoryfor executing the computer executable instructions for causing theelectronic musical apparatus to reproduce encrypted music contents by:loading an encrypted music content from one of the music contentsources, wherein the encrypted music content includes encrypted commonkey information, encrypted security information, and encrypted musicpiece information, wherein the encrypted common key information isencrypted with a secret key, and wherein the encrypted securityinformation includes copyright information and content ID; determining atype of the one of the music content sources; retrieving a source ID forthe determined type of the one of the music content sources and thesecret key from the storage device; retrieving the encrypted common keyinformation, decrypting the encrypted common key information using theretrieved secret key, and retrieving the common key from the decryptedcommon key information; generating a first key using the retrievedcommon key and the retrieved source ID; retrieving the encryptedsecurity information, decrypting the encrypted security informationusing the first key, and retrieving the content ID from the decryptedsecurity information; and decrypting the encrypted music pieceinformation using the retrieved content ID and reproducing the decryptedmusic piece information.
 2. The electronic musical apparatus as claimedin claim 1, wherein the retrieved content ID comprises a second key fordecrypting the encrypted music piece information.
 3. A non-transitorycomputer-readable storage medium storing a computer executableinstructions for reproducing encrypted music contents received from anyone of plural types of music content sources, wherein the computerexecutable instructions when executed by an electronic musical apparatuscauses the electronic musical apparatus to perform the method steps of:loading an encrypted music content from one of the music contentsources, wherein the encrypted music content includes encrypted commonkey information, encrypted security information, and encrypted musicpiece information, wherein the encrypted common key is encrypted with asecret key, and wherein the encrypted security information includescopyright information and content ID; determining a type of the one ofthe music content sources retrieving a source ID for the determined typeof the one of the music content sources and the secret key from astorage device for storing the secret key and a plurality of source IDseach unique to one of the plurality types of music content sources;retrieving the encrypted common key information, decrypting theencrypted common key information using the retrieved secret key, andretrieving the common key from the decrypted common key information;generating a first key using the retrieved common key and the retrievedsource ID; retrieving the encrypted security information, decrypting theencrypted security information using the first key, and retrieving thecontent ID from the decrypted security information; and decrypting theencrypted music piece information using the retrieved content ID andreproducing the decrypted music piece information.
 4. The non-transitorycomputer-readable storage medium as claimed in claim 3, wherein theretrieved content ID comprises a second key for decrypting the encryptedmusic piece information.
 5. A method of reproducing encrypted musiccontents received from any one of plural types of music content sourcesin an electronic musical apparatus, the method comprising the steps of:loading, into the electronic musical apparatus, an encrypted musiccontent from one of the music content sources, wherein the encryptedmusic content includes encrypted common key information, encryptedsecurity information, and encrypted music piece information, wherein theencrypted common key information is encrypted with a secret key, whereinthe encrypted security information includes copyright information andcontent ID, and wherein the electronic musical apparatus includes astorage device; determining, by the electronic musical apparatus, a typeof the one of the music content sources; retrieving, by the electronicmusical apparatus, a source ID for the determined type of the one of themusic content sources and the secret key from a storage device forstoring the secret key and a plurality of source IDs each unique to oneof the plurality types of music content sources; retrieving, by theelectronic musical apparatus, the encrypted common key information,decrypting the encrypted common key information using the retrievedsecret key, and retrieving the common key from the decrypted common keyinformation; generating, by the electronic musical apparatus, a firstkey using the retrieved common key and the retrieved source ID;retrieving, by the electronic musical apparatus, the encrypted securityinformation, decrypting the encrypted security information using thefirst key, and retrieving the content ID from the decrypted securityinformation; and decrypting, by the electronic musical apparatus, theencrypted music piece information using the retrieved content ID andreproducing the decrypted music piece information.
 6. The method asclaimed in claim 5, wherein the retrieved content ID comprises a secondkey for decrypting the encrypted music piece information.